a = 0
b = 0
c = 0

a = 1
GOSUB sub1
c = c * 2
a = 2
GOTO end_loop

sub1:
    b = 1
    GOSUB sub2
    b = b * 2

    RETURN
    b = 5
    END

end_loop:
    IF a == 2 AND b == 2 AND c == 2 THEN
        PRINT "success"
    ELSE
        PRINT "fail: ", a, ", ", b, ", ", c
    END IF
    PRINT_FLUSH(message1)
    GOTO end_loop

sub2:
    c = 1
    RETURN
    c = 5